The patch titled
Subject: kexec: split kexec_file syscall code to kexec_file.c
has been added to the -mm tree. Its filename is
kexec-split-kexec_file-syscall-code-to-kexec_filec.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/kexec-split-kexec_file-syscall-code-to-kexec_filec.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/kexec-split-kexec_file-syscall-code-to-kexec_filec.patch
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*** Remember to use Documentation/SubmitChecklist when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: dyoung@xxxxxxxxxx
Subject: kexec: split kexec_file syscall code to kexec_file.c
Previously Theodore Ts'o brought up an issue about kexec_load syscall
bypassing signature verification: https://lkml.org/lkml/2015/6/14/280
Because we have two kexec load syscall, one kexec_load, another
kexec_file_load, the latter one was introduced by Vivek Goyal, it is
mainly for supporting UEFI secure boot. kexec_file_load verifies kernel
signature, but even if with CONFIG_KEXEC_VERIFY_SIG=y and
CONFIG_KEXEC_FILE=y, kexec-tools still can use old syscall and bypass
signature verification.
KEXEC_FILE can also be used without UEFI, so kexec can always verify
kernel signature for security purpose.
The suggestion in above thread is add a new Kconfig option for kexec
common code, here I use KEXEC_CORE, KEXEC and KEXEC_FILE select KEXEC_CORE
so one can compile only KEXEC_FILE without old kexec_load syscall.
Tested kexec_load only, kexec_file_load only, kexec and kexec_file_load
built in cases in x86. For kexec_file_load, tested signed and un-signed
kernel. Tested kexec_load in powerpc64 arch. Build tested arm arch.
For kexec_file_load, if you do not specify "-s" in kexec-tools, kexec load
will hang, though "-s" is mandatory for kexec_file_load, kexec should
still fail out instead of hanging there, here is a fix in kexec-tools:
: --- kexec-tools.orig/kexec/crashdump-elf.c
: +++ kexec-tools/kexec/crashdump-elf.c
: @@ -145,11 +145,12 @@ int FUNC(struct kexec_info *info,
:
: count_cpu = nr_cpus;
: for (i = 0; count_cpu > 0; i++) {
: - if (get_note_info(i, ¬es_addr, ¬es_len) < 0) {
: - /* This cpu is not present. Skip it. */
: - continue;
: - }
: + int ret;
: +
: + ret = get_note_info(i, ¬es_addr, ¬es_len);
: count_cpu--;
: + if (ret < 0) /* This cpu is not present. Skip it. */
: + continue;
:
: phdr = (PHDR *) bufp;
: bufp += sizeof(PHDR);
This patch (of 2):
Split kexec_file syscall related code to another file kernel/kexec_file.c
so that the #ifdef CONFIG_KEXEC_FILE in kexec.c can be dropped.
Sharing variables and functions are moved to kernel/kexec_internal.h per
suggestion from Vivek and Petr.
Signed-off-by: Dave Young <dyoung@xxxxxxxxxx>
Cc: Eric W. Biederman <ebiederm@xxxxxxxxxxxx>
Cc: Vivek Goyal <vgoyal@xxxxxxxxxx>
Cc: Petr Tesarik <ptesarik@xxxxxxx>
Cc: Theodore Ts'o <tytso@xxxxxxx>
Cc: Josh Boyer <jwboyer@xxxxxxxxxxxxxxxxx>
Cc: David Howells <dhowells@xxxxxxxxxx>
Cc: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/Makefile | 1
kernel/kexec.c | 1055 --------------------------------------
kernel/kexec_file.c | 1044 +++++++++++++++++++++++++++++++++++++
kernel/kexec_internal.h | 22
4 files changed, 1077 insertions(+), 1045 deletions(-)
diff -puN kernel/Makefile~kexec-split-kexec_file-syscall-code-to-kexec_filec kernel/Makefile
--- a/kernel/Makefile~kexec-split-kexec_file-syscall-code-to-kexec_filec
+++ a/kernel/Makefile
@@ -51,6 +51,7 @@ obj-$(CONFIG_MODULE_SIG) += module_signi
obj-$(CONFIG_KALLSYMS) += kallsyms.o
obj-$(CONFIG_BSD_PROCESS_ACCT) += acct.o
obj-$(CONFIG_KEXEC) += kexec.o
+obj-$(CONFIG_KEXEC_FILE) += kexec_file.o
obj-$(CONFIG_BACKTRACE_SELF_TEST) += backtracetest.o
obj-$(CONFIG_COMPAT) += compat.o
obj-$(CONFIG_CGROUPS) += cgroup.o
diff -puN kernel/kexec.c~kexec-split-kexec_file-syscall-code-to-kexec_filec kernel/kexec.c
--- a/kernel/kexec.c~kexec-split-kexec_file-syscall-code-to-kexec_filec
+++ a/kernel/kexec.c
@@ -31,7 +31,6 @@
#include <linux/pm.h>
#include <linux/cpu.h>
#include <linux/console.h>
-#include <linux/vmalloc.h>
#include <linux/swap.h>
#include <linux/syscore_ops.h>
#include <linux/compiler.h>
@@ -44,6 +43,9 @@
#include <crypto/hash.h>
#include <crypto/sha.h>
+#include "kexec_internal.h"
+
+DEFINE_MUTEX(kexec_mutex);
/* Per cpu memory for storing cpu states in case of system crash. */
note_buf_t __percpu *crash_notes;
@@ -57,16 +59,6 @@ size_t vmcoreinfo_max_size = sizeof(vmco
/* Flag to indicate we are going to kexec a new kernel */
bool kexec_in_progress = false;
-/*
- * Declare these symbols weak so that if architecture provides a purgatory,
- * these will be overridden.
- */
-char __weak kexec_purgatory[0];
-size_t __weak kexec_purgatory_size = 0;
-
-#ifdef CONFIG_KEXEC_FILE
-static int kexec_calculate_store_digests(struct kimage *image);
-#endif
/* Location of the reserved area for the crash kernel */
struct resource crashk_res = {
@@ -146,8 +138,6 @@ int kexec_should_crash(struct task_struc
*/
#define KIMAGE_NO_DEST (-1UL)
-static int kimage_is_destination_range(struct kimage *image,
- unsigned long start, unsigned long end);
static struct page *kimage_alloc_page(struct kimage *image,
gfp_t gfp_mask,
unsigned long dest);
@@ -169,7 +159,7 @@ static int copy_user_segment_list(struct
return ret;
}
-static int sanity_check_segment_list(struct kimage *image)
+int sanity_check_segment_list(struct kimage *image)
{
int result, i;
unsigned long nr_segments = image->nr_segments;
@@ -259,7 +249,7 @@ static int sanity_check_segment_list(str
return 0;
}
-static struct kimage *do_kimage_alloc_init(void)
+struct kimage *do_kimage_alloc_init(void)
{
struct kimage *image;
@@ -286,8 +276,6 @@ static struct kimage *do_kimage_alloc_in
return image;
}
-static void kimage_free_page_list(struct list_head *list);
-
static int kimage_alloc_init(struct kimage **rimage, unsigned long entry,
unsigned long nr_segments,
struct kexec_segment __user *segments,
@@ -354,283 +342,7 @@ out_free_image:
return ret;
}
-#ifdef CONFIG_KEXEC_FILE
-static int copy_file_from_fd(int fd, void **buf, unsigned long *buf_len)
-{
- struct fd f = fdget(fd);
- int ret;
- struct kstat stat;
- loff_t pos;
- ssize_t bytes = 0;
-
- if (!f.file)
- return -EBADF;
-
- ret = vfs_getattr(&f.file->f_path, &stat);
- if (ret)
- goto out;
-
- if (stat.size > INT_MAX) {
- ret = -EFBIG;
- goto out;
- }
-
- /* Don't hand 0 to vmalloc, it whines. */
- if (stat.size == 0) {
- ret = -EINVAL;
- goto out;
- }
-
- *buf = vmalloc(stat.size);
- if (!*buf) {
- ret = -ENOMEM;
- goto out;
- }
-
- pos = 0;
- while (pos < stat.size) {
- bytes = kernel_read(f.file, pos, (char *)(*buf) + pos,
- stat.size - pos);
- if (bytes < 0) {
- vfree(*buf);
- ret = bytes;
- goto out;
- }
-
- if (bytes == 0)
- break;
- pos += bytes;
- }
-
- if (pos != stat.size) {
- ret = -EBADF;
- vfree(*buf);
- goto out;
- }
-
- *buf_len = pos;
-out:
- fdput(f);
- return ret;
-}
-
-/* Architectures can provide this probe function */
-int __weak arch_kexec_kernel_image_probe(struct kimage *image, void *buf,
- unsigned long buf_len)
-{
- return -ENOEXEC;
-}
-
-void * __weak arch_kexec_kernel_image_load(struct kimage *image)
-{
- return ERR_PTR(-ENOEXEC);
-}
-
-void __weak arch_kimage_file_post_load_cleanup(struct kimage *image)
-{
-}
-
-int __weak arch_kexec_kernel_verify_sig(struct kimage *image, void *buf,
- unsigned long buf_len)
-{
- return -EKEYREJECTED;
-}
-
-/* Apply relocations of type RELA */
-int __weak
-arch_kexec_apply_relocations_add(const Elf_Ehdr *ehdr, Elf_Shdr *sechdrs,
- unsigned int relsec)
-{
- pr_err("RELA relocation unsupported.\n");
- return -ENOEXEC;
-}
-
-/* Apply relocations of type REL */
-int __weak
-arch_kexec_apply_relocations(const Elf_Ehdr *ehdr, Elf_Shdr *sechdrs,
- unsigned int relsec)
-{
- pr_err("REL relocation unsupported.\n");
- return -ENOEXEC;
-}
-
-/*
- * Free up memory used by kernel, initrd, and command line. This is temporary
- * memory allocation which is not needed any more after these buffers have
- * been loaded into separate segments and have been copied elsewhere.
- */
-static void kimage_file_post_load_cleanup(struct kimage *image)
-{
- struct purgatory_info *pi = &image->purgatory_info;
-
- vfree(image->kernel_buf);
- image->kernel_buf = NULL;
-
- vfree(image->initrd_buf);
- image->initrd_buf = NULL;
-
- kfree(image->cmdline_buf);
- image->cmdline_buf = NULL;
-
- vfree(pi->purgatory_buf);
- pi->purgatory_buf = NULL;
-
- vfree(pi->sechdrs);
- pi->sechdrs = NULL;
-
- /* See if architecture has anything to cleanup post load */
- arch_kimage_file_post_load_cleanup(image);
-
- /*
- * Above call should have called into bootloader to free up
- * any data stored in kimage->image_loader_data. It should
- * be ok now to free it up.
- */
- kfree(image->image_loader_data);
- image->image_loader_data = NULL;
-}
-
-/*
- * In file mode list of segments is prepared by kernel. Copy relevant
- * data from user space, do error checking, prepare segment list
- */
-static int
-kimage_file_prepare_segments(struct kimage *image, int kernel_fd, int initrd_fd,
- const char __user *cmdline_ptr,
- unsigned long cmdline_len, unsigned flags)
-{
- int ret = 0;
- void *ldata;
-
- ret = copy_file_from_fd(kernel_fd, &image->kernel_buf,
- &image->kernel_buf_len);
- if (ret)
- return ret;
-
- /* Call arch image probe handlers */
- ret = arch_kexec_kernel_image_probe(image, image->kernel_buf,
- image->kernel_buf_len);
-
- if (ret)
- goto out;
-
-#ifdef CONFIG_KEXEC_VERIFY_SIG
- ret = arch_kexec_kernel_verify_sig(image, image->kernel_buf,
- image->kernel_buf_len);
- if (ret) {
- pr_debug("kernel signature verification failed.\n");
- goto out;
- }
- pr_debug("kernel signature verification successful.\n");
-#endif
- /* It is possible that there no initramfs is being loaded */
- if (!(flags & KEXEC_FILE_NO_INITRAMFS)) {
- ret = copy_file_from_fd(initrd_fd, &image->initrd_buf,
- &image->initrd_buf_len);
- if (ret)
- goto out;
- }
-
- if (cmdline_len) {
- image->cmdline_buf = kzalloc(cmdline_len, GFP_KERNEL);
- if (!image->cmdline_buf) {
- ret = -ENOMEM;
- goto out;
- }
-
- ret = copy_from_user(image->cmdline_buf, cmdline_ptr,
- cmdline_len);
- if (ret) {
- ret = -EFAULT;
- goto out;
- }
-
- image->cmdline_buf_len = cmdline_len;
-
- /* command line should be a string with last byte null */
- if (image->cmdline_buf[cmdline_len - 1] != '\0') {
- ret = -EINVAL;
- goto out;
- }
- }
-
- /* Call arch image load handlers */
- ldata = arch_kexec_kernel_image_load(image);
-
- if (IS_ERR(ldata)) {
- ret = PTR_ERR(ldata);
- goto out;
- }
-
- image->image_loader_data = ldata;
-out:
- /* In case of error, free up all allocated memory in this function */
- if (ret)
- kimage_file_post_load_cleanup(image);
- return ret;
-}
-
-static int
-kimage_file_alloc_init(struct kimage **rimage, int kernel_fd,
- int initrd_fd, const char __user *cmdline_ptr,
- unsigned long cmdline_len, unsigned long flags)
-{
- int ret;
- struct kimage *image;
- bool kexec_on_panic = flags & KEXEC_FILE_ON_CRASH;
-
- image = do_kimage_alloc_init();
- if (!image)
- return -ENOMEM;
-
- image->file_mode = 1;
-
- if (kexec_on_panic) {
- /* Enable special crash kernel control page alloc policy. */
- image->control_page = crashk_res.start;
- image->type = KEXEC_TYPE_CRASH;
- }
-
- ret = kimage_file_prepare_segments(image, kernel_fd, initrd_fd,
- cmdline_ptr, cmdline_len, flags);
- if (ret)
- goto out_free_image;
-
- ret = sanity_check_segment_list(image);
- if (ret)
- goto out_free_post_load_bufs;
-
- ret = -ENOMEM;
- image->control_code_page = kimage_alloc_control_pages(image,
- get_order(KEXEC_CONTROL_PAGE_SIZE));
- if (!image->control_code_page) {
- pr_err("Could not allocate control_code_buffer\n");
- goto out_free_post_load_bufs;
- }
-
- if (!kexec_on_panic) {
- image->swap_page = kimage_alloc_control_pages(image, 0);
- if (!image->swap_page) {
- pr_err("Could not allocate swap buffer\n");
- goto out_free_control_pages;
- }
- }
-
- *rimage = image;
- return 0;
-out_free_control_pages:
- kimage_free_page_list(&image->control_pages);
-out_free_post_load_bufs:
- kimage_file_post_load_cleanup(image);
-out_free_image:
- kfree(image);
- return ret;
-}
-#else /* CONFIG_KEXEC_FILE */
-static inline void kimage_file_post_load_cleanup(struct kimage *image) { }
-#endif /* CONFIG_KEXEC_FILE */
-
-static int kimage_is_destination_range(struct kimage *image,
+int kimage_is_destination_range(struct kimage *image,
unsigned long start,
unsigned long end)
{
@@ -676,7 +388,7 @@ static void kimage_free_pages(struct pag
__free_pages(page, order);
}
-static void kimage_free_page_list(struct list_head *list)
+void kimage_free_page_list(struct list_head *list)
{
struct list_head *pos, *next;
@@ -892,7 +604,7 @@ static void kimage_free_extra_pages(stru
kimage_free_page_list(&image->unusable_pages);
}
-static void kimage_terminate(struct kimage *image)
+void kimage_terminate(struct kimage *image)
{
if (*image->entry != 0)
image->entry++;
@@ -913,7 +625,7 @@ static void kimage_free_entry(kimage_ent
kimage_free_pages(page);
}
-static void kimage_free(struct kimage *image)
+void kimage_free(struct kimage *image)
{
kimage_entry_t *ptr, entry;
kimage_entry_t ind = 0;
@@ -1204,7 +916,7 @@ out:
return result;
}
-static int kimage_load_segment(struct kimage *image,
+int kimage_load_segment(struct kimage *image,
struct kexec_segment *segment)
{
int result = -ENOMEM;
@@ -1245,8 +957,6 @@ struct kimage *kexec_image;
struct kimage *kexec_crash_image;
int kexec_load_disabled;
-static DEFINE_MUTEX(kexec_mutex);
-
SYSCALL_DEFINE4(kexec_load, unsigned long, entry, unsigned long, nr_segments,
struct kexec_segment __user *, segments, unsigned long, flags)
{
@@ -1391,85 +1101,6 @@ COMPAT_SYSCALL_DEFINE4(kexec_load, compa
}
#endif
-#ifdef CONFIG_KEXEC_FILE
-SYSCALL_DEFINE5(kexec_file_load, int, kernel_fd, int, initrd_fd,
- unsigned long, cmdline_len, const char __user *, cmdline_ptr,
- unsigned long, flags)
-{
- int ret = 0, i;
- struct kimage **dest_image, *image;
-
- /* We only trust the superuser with rebooting the system. */
- if (!capable(CAP_SYS_BOOT) || kexec_load_disabled)
- return -EPERM;
-
- /* Make sure we have a legal set of flags */
- if (flags != (flags & KEXEC_FILE_FLAGS))
- return -EINVAL;
-
- image = NULL;
-
- if (!mutex_trylock(&kexec_mutex))
- return -EBUSY;
-
- dest_image = &kexec_image;
- if (flags & KEXEC_FILE_ON_CRASH)
- dest_image = &kexec_crash_image;
-
- if (flags & KEXEC_FILE_UNLOAD)
- goto exchange;
-
- /*
- * In case of crash, new kernel gets loaded in reserved region. It is
- * same memory where old crash kernel might be loaded. Free any
- * current crash dump kernel before we corrupt it.
- */
- if (flags & KEXEC_FILE_ON_CRASH)
- kimage_free(xchg(&kexec_crash_image, NULL));
-
- ret = kimage_file_alloc_init(&image, kernel_fd, initrd_fd, cmdline_ptr,
- cmdline_len, flags);
- if (ret)
- goto out;
-
- ret = machine_kexec_prepare(image);
- if (ret)
- goto out;
-
- ret = kexec_calculate_store_digests(image);
- if (ret)
- goto out;
-
- for (i = 0; i < image->nr_segments; i++) {
- struct kexec_segment *ksegment;
-
- ksegment = &image->segment[i];
- pr_debug("Loading segment %d: buf=0x%p bufsz=0x%zx mem=0x%lx memsz=0x%zx\n",
- i, ksegment->buf, ksegment->bufsz, ksegment->mem,
- ksegment->memsz);
-
- ret = kimage_load_segment(image, &image->segment[i]);
- if (ret)
- goto out;
- }
-
- kimage_terminate(image);
-
- /*
- * Free up any temporary buffers allocated which are not needed
- * after image has been loaded
- */
- kimage_file_post_load_cleanup(image);
-exchange:
- image = xchg(dest_image, image);
-out:
- mutex_unlock(&kexec_mutex);
- kimage_free(image);
- return ret;
-}
-
-#endif /* CONFIG_KEXEC_FILE */
-
void crash_kexec(struct pt_regs *regs)
{
/* Take the kexec_mutex here to prevent sys_kexec_load
@@ -2024,672 +1655,6 @@ static int __init crash_save_vmcoreinfo_
subsys_initcall(crash_save_vmcoreinfo_init);
-#ifdef CONFIG_KEXEC_FILE
-static int locate_mem_hole_top_down(unsigned long start, unsigned long end,
- struct kexec_buf *kbuf)
-{
- struct kimage *image = kbuf->image;
- unsigned long temp_start, temp_end;
-
- temp_end = min(end, kbuf->buf_max);
- temp_start = temp_end - kbuf->memsz;
-
- do {
- /* align down start */
- temp_start = temp_start & (~(kbuf->buf_align - 1));
-
- if (temp_start < start || temp_start < kbuf->buf_min)
- return 0;
-
- temp_end = temp_start + kbuf->memsz - 1;
-
- /*
- * Make sure this does not conflict with any of existing
- * segments
- */
- if (kimage_is_destination_range(image, temp_start, temp_end)) {
- temp_start = temp_start - PAGE_SIZE;
- continue;
- }
-
- /* We found a suitable memory range */
- break;
- } while (1);
-
- /* If we are here, we found a suitable memory range */
- kbuf->mem = temp_start;
-
- /* Success, stop navigating through remaining System RAM ranges */
- return 1;
-}
-
-static int locate_mem_hole_bottom_up(unsigned long start, unsigned long end,
- struct kexec_buf *kbuf)
-{
- struct kimage *image = kbuf->image;
- unsigned long temp_start, temp_end;
-
- temp_start = max(start, kbuf->buf_min);
-
- do {
- temp_start = ALIGN(temp_start, kbuf->buf_align);
- temp_end = temp_start + kbuf->memsz - 1;
-
- if (temp_end > end || temp_end > kbuf->buf_max)
- return 0;
- /*
- * Make sure this does not conflict with any of existing
- * segments
- */
- if (kimage_is_destination_range(image, temp_start, temp_end)) {
- temp_start = temp_start + PAGE_SIZE;
- continue;
- }
-
- /* We found a suitable memory range */
- break;
- } while (1);
-
- /* If we are here, we found a suitable memory range */
- kbuf->mem = temp_start;
-
- /* Success, stop navigating through remaining System RAM ranges */
- return 1;
-}
-
-static int locate_mem_hole_callback(u64 start, u64 end, void *arg)
-{
- struct kexec_buf *kbuf = (struct kexec_buf *)arg;
- unsigned long sz = end - start + 1;
-
- /* Returning 0 will take to next memory range */
- if (sz < kbuf->memsz)
- return 0;
-
- if (end < kbuf->buf_min || start > kbuf->buf_max)
- return 0;
-
- /*
- * Allocate memory top down with-in ram range. Otherwise bottom up
- * allocation.
- */
- if (kbuf->top_down)
- return locate_mem_hole_top_down(start, end, kbuf);
- return locate_mem_hole_bottom_up(start, end, kbuf);
-}
-
-/*
- * Helper function for placing a buffer in a kexec segment. This assumes
- * that kexec_mutex is held.
- */
-int kexec_add_buffer(struct kimage *image, char *buffer, unsigned long bufsz,
- unsigned long memsz, unsigned long buf_align,
- unsigned long buf_min, unsigned long buf_max,
- bool top_down, unsigned long *load_addr)
-{
-
- struct kexec_segment *ksegment;
- struct kexec_buf buf, *kbuf;
- int ret;
-
- /* Currently adding segment this way is allowed only in file mode */
- if (!image->file_mode)
- return -EINVAL;
-
- if (image->nr_segments >= KEXEC_SEGMENT_MAX)
- return -EINVAL;
-
- /*
- * Make sure we are not trying to add buffer after allocating
- * control pages. All segments need to be placed first before
- * any control pages are allocated. As control page allocation
- * logic goes through list of segments to make sure there are
- * no destination overlaps.
- */
- if (!list_empty(&image->control_pages)) {
- WARN_ON(1);
- return -EINVAL;
- }
-
- memset(&buf, 0, sizeof(struct kexec_buf));
- kbuf = &buf;
- kbuf->image = image;
- kbuf->buffer = buffer;
- kbuf->bufsz = bufsz;
-
- kbuf->memsz = ALIGN(memsz, PAGE_SIZE);
- kbuf->buf_align = max(buf_align, PAGE_SIZE);
- kbuf->buf_min = buf_min;
- kbuf->buf_max = buf_max;
- kbuf->top_down = top_down;
-
- /* Walk the RAM ranges and allocate a suitable range for the buffer */
- if (image->type == KEXEC_TYPE_CRASH)
- ret = walk_iomem_res("Crash kernel",
- IORESOURCE_MEM | IORESOURCE_BUSY,
- crashk_res.start, crashk_res.end, kbuf,
- locate_mem_hole_callback);
- else
- ret = walk_system_ram_res(0, -1, kbuf,
- locate_mem_hole_callback);
- if (ret != 1) {
- /* A suitable memory range could not be found for buffer */
- return -EADDRNOTAVAIL;
- }
-
- /* Found a suitable memory range */
- ksegment = &image->segment[image->nr_segments];
- ksegment->kbuf = kbuf->buffer;
- ksegment->bufsz = kbuf->bufsz;
- ksegment->mem = kbuf->mem;
- ksegment->memsz = kbuf->memsz;
- image->nr_segments++;
- *load_addr = ksegment->mem;
- return 0;
-}
-
-/* Calculate and store the digest of segments */
-static int kexec_calculate_store_digests(struct kimage *image)
-{
- struct crypto_shash *tfm;
- struct shash_desc *desc;
- int ret = 0, i, j, zero_buf_sz, sha_region_sz;
- size_t desc_size, nullsz;
- char *digest;
- void *zero_buf;
- struct kexec_sha_region *sha_regions;
- struct purgatory_info *pi = &image->purgatory_info;
-
- zero_buf = __va(page_to_pfn(ZERO_PAGE(0)) << PAGE_SHIFT);
- zero_buf_sz = PAGE_SIZE;
-
- tfm = crypto_alloc_shash("sha256", 0, 0);
- if (IS_ERR(tfm)) {
- ret = PTR_ERR(tfm);
- goto out;
- }
-
- desc_size = crypto_shash_descsize(tfm) + sizeof(*desc);
- desc = kzalloc(desc_size, GFP_KERNEL);
- if (!desc) {
- ret = -ENOMEM;
- goto out_free_tfm;
- }
-
- sha_region_sz = KEXEC_SEGMENT_MAX * sizeof(struct kexec_sha_region);
- sha_regions = vzalloc(sha_region_sz);
- if (!sha_regions)
- goto out_free_desc;
-
- desc->tfm = tfm;
- desc->flags = 0;
-
- ret = crypto_shash_init(desc);
- if (ret < 0)
- goto out_free_sha_regions;
-
- digest = kzalloc(SHA256_DIGEST_SIZE, GFP_KERNEL);
- if (!digest) {
- ret = -ENOMEM;
- goto out_free_sha_regions;
- }
-
- for (j = i = 0; i < image->nr_segments; i++) {
- struct kexec_segment *ksegment;
-
- ksegment = &image->segment[i];
- /*
- * Skip purgatory as it will be modified once we put digest
- * info in purgatory.
- */
- if (ksegment->kbuf == pi->purgatory_buf)
- continue;
-
- ret = crypto_shash_update(desc, ksegment->kbuf,
- ksegment->bufsz);
- if (ret)
- break;
-
- /*
- * Assume rest of the buffer is filled with zero and
- * update digest accordingly.
- */
- nullsz = ksegment->memsz - ksegment->bufsz;
- while (nullsz) {
- unsigned long bytes = nullsz;
-
- if (bytes > zero_buf_sz)
- bytes = zero_buf_sz;
- ret = crypto_shash_update(desc, zero_buf, bytes);
- if (ret)
- break;
- nullsz -= bytes;
- }
-
- if (ret)
- break;
-
- sha_regions[j].start = ksegment->mem;
- sha_regions[j].len = ksegment->memsz;
- j++;
- }
-
- if (!ret) {
- ret = crypto_shash_final(desc, digest);
- if (ret)
- goto out_free_digest;
- ret = kexec_purgatory_get_set_symbol(image, "sha_regions",
- sha_regions, sha_region_sz, 0);
- if (ret)
- goto out_free_digest;
-
- ret = kexec_purgatory_get_set_symbol(image, "sha256_digest",
- digest, SHA256_DIGEST_SIZE, 0);
- if (ret)
- goto out_free_digest;
- }
-
-out_free_digest:
- kfree(digest);
-out_free_sha_regions:
- vfree(sha_regions);
-out_free_desc:
- kfree(desc);
-out_free_tfm:
- kfree(tfm);
-out:
- return ret;
-}
-
-/* Actually load purgatory. Lot of code taken from kexec-tools */
-static int __kexec_load_purgatory(struct kimage *image, unsigned long min,
- unsigned long max, int top_down)
-{
- struct purgatory_info *pi = &image->purgatory_info;
- unsigned long align, buf_align, bss_align, buf_sz, bss_sz, bss_pad;
- unsigned long memsz, entry, load_addr, curr_load_addr, bss_addr, offset;
- unsigned char *buf_addr, *src;
- int i, ret = 0, entry_sidx = -1;
- const Elf_Shdr *sechdrs_c;
- Elf_Shdr *sechdrs = NULL;
- void *purgatory_buf = NULL;
-
- /*
- * sechdrs_c points to section headers in purgatory and are read
- * only. No modifications allowed.
- */
- sechdrs_c = (void *)pi->ehdr + pi->ehdr->e_shoff;
-
- /*
- * We can not modify sechdrs_c[] and its fields. It is read only.
- * Copy it over to a local copy where one can store some temporary
- * data and free it at the end. We need to modify ->sh_addr and
- * ->sh_offset fields to keep track of permanent and temporary
- * locations of sections.
- */
- sechdrs = vzalloc(pi->ehdr->e_shnum * sizeof(Elf_Shdr));
- if (!sechdrs)
- return -ENOMEM;
-
- memcpy(sechdrs, sechdrs_c, pi->ehdr->e_shnum * sizeof(Elf_Shdr));
-
- /*
- * We seem to have multiple copies of sections. First copy is which
- * is embedded in kernel in read only section. Some of these sections
- * will be copied to a temporary buffer and relocated. And these
- * sections will finally be copied to their final destination at
- * segment load time.
- *
- * Use ->sh_offset to reflect section address in memory. It will
- * point to original read only copy if section is not allocatable.
- * Otherwise it will point to temporary copy which will be relocated.
- *
- * Use ->sh_addr to contain final address of the section where it
- * will go during execution time.
- */
- for (i = 0; i < pi->ehdr->e_shnum; i++) {
- if (sechdrs[i].sh_type == SHT_NOBITS)
- continue;
-
- sechdrs[i].sh_offset = (unsigned long)pi->ehdr +
- sechdrs[i].sh_offset;
- }
-
- /*
- * Identify entry point section and make entry relative to section
- * start.
- */
- entry = pi->ehdr->e_entry;
- for (i = 0; i < pi->ehdr->e_shnum; i++) {
- if (!(sechdrs[i].sh_flags & SHF_ALLOC))
- continue;
-
- if (!(sechdrs[i].sh_flags & SHF_EXECINSTR))
- continue;
-
- /* Make entry section relative */
- if (sechdrs[i].sh_addr <= pi->ehdr->e_entry &&
- ((sechdrs[i].sh_addr + sechdrs[i].sh_size) >
- pi->ehdr->e_entry)) {
- entry_sidx = i;
- entry -= sechdrs[i].sh_addr;
- break;
- }
- }
-
- /* Determine how much memory is needed to load relocatable object. */
- buf_align = 1;
- bss_align = 1;
- buf_sz = 0;
- bss_sz = 0;
-
- for (i = 0; i < pi->ehdr->e_shnum; i++) {
- if (!(sechdrs[i].sh_flags & SHF_ALLOC))
- continue;
-
- align = sechdrs[i].sh_addralign;
- if (sechdrs[i].sh_type != SHT_NOBITS) {
- if (buf_align < align)
- buf_align = align;
- buf_sz = ALIGN(buf_sz, align);
- buf_sz += sechdrs[i].sh_size;
- } else {
- /* bss section */
- if (bss_align < align)
- bss_align = align;
- bss_sz = ALIGN(bss_sz, align);
- bss_sz += sechdrs[i].sh_size;
- }
- }
-
- /* Determine the bss padding required to align bss properly */
- bss_pad = 0;
- if (buf_sz & (bss_align - 1))
- bss_pad = bss_align - (buf_sz & (bss_align - 1));
-
- memsz = buf_sz + bss_pad + bss_sz;
-
- /* Allocate buffer for purgatory */
- purgatory_buf = vzalloc(buf_sz);
- if (!purgatory_buf) {
- ret = -ENOMEM;
- goto out;
- }
-
- if (buf_align < bss_align)
- buf_align = bss_align;
-
- /* Add buffer to segment list */
- ret = kexec_add_buffer(image, purgatory_buf, buf_sz, memsz,
- buf_align, min, max, top_down,
- &pi->purgatory_load_addr);
- if (ret)
- goto out;
-
- /* Load SHF_ALLOC sections */
- buf_addr = purgatory_buf;
- load_addr = curr_load_addr = pi->purgatory_load_addr;
- bss_addr = load_addr + buf_sz + bss_pad;
-
- for (i = 0; i < pi->ehdr->e_shnum; i++) {
- if (!(sechdrs[i].sh_flags & SHF_ALLOC))
- continue;
-
- align = sechdrs[i].sh_addralign;
- if (sechdrs[i].sh_type != SHT_NOBITS) {
- curr_load_addr = ALIGN(curr_load_addr, align);
- offset = curr_load_addr - load_addr;
- /* We already modifed ->sh_offset to keep src addr */
- src = (char *) sechdrs[i].sh_offset;
- memcpy(buf_addr + offset, src, sechdrs[i].sh_size);
-
- /* Store load address and source address of section */
- sechdrs[i].sh_addr = curr_load_addr;
-
- /*
- * This section got copied to temporary buffer. Update
- * ->sh_offset accordingly.
- */
- sechdrs[i].sh_offset = (unsigned long)(buf_addr + offset);
-
- /* Advance to the next address */
- curr_load_addr += sechdrs[i].sh_size;
- } else {
- bss_addr = ALIGN(bss_addr, align);
- sechdrs[i].sh_addr = bss_addr;
- bss_addr += sechdrs[i].sh_size;
- }
- }
-
- /* Update entry point based on load address of text section */
- if (entry_sidx >= 0)
- entry += sechdrs[entry_sidx].sh_addr;
-
- /* Make kernel jump to purgatory after shutdown */
- image->start = entry;
-
- /* Used later to get/set symbol values */
- pi->sechdrs = sechdrs;
-
- /*
- * Used later to identify which section is purgatory and skip it
- * from checksumming.
- */
- pi->purgatory_buf = purgatory_buf;
- return ret;
-out:
- vfree(sechdrs);
- vfree(purgatory_buf);
- return ret;
-}
-
-static int kexec_apply_relocations(struct kimage *image)
-{
- int i, ret;
- struct purgatory_info *pi = &image->purgatory_info;
- Elf_Shdr *sechdrs = pi->sechdrs;
-
- /* Apply relocations */
- for (i = 0; i < pi->ehdr->e_shnum; i++) {
- Elf_Shdr *section, *symtab;
-
- if (sechdrs[i].sh_type != SHT_RELA &&
- sechdrs[i].sh_type != SHT_REL)
- continue;
-
- /*
- * For section of type SHT_RELA/SHT_REL,
- * ->sh_link contains section header index of associated
- * symbol table. And ->sh_info contains section header
- * index of section to which relocations apply.
- */
- if (sechdrs[i].sh_info >= pi->ehdr->e_shnum ||
- sechdrs[i].sh_link >= pi->ehdr->e_shnum)
- return -ENOEXEC;
-
- section = &sechdrs[sechdrs[i].sh_info];
- symtab = &sechdrs[sechdrs[i].sh_link];
-
- if (!(section->sh_flags & SHF_ALLOC))
- continue;
-
- /*
- * symtab->sh_link contain section header index of associated
- * string table.
- */
- if (symtab->sh_link >= pi->ehdr->e_shnum)
- /* Invalid section number? */
- continue;
-
- /*
- * Respective architecture needs to provide support for applying
- * relocations of type SHT_RELA/SHT_REL.
- */
- if (sechdrs[i].sh_type == SHT_RELA)
- ret = arch_kexec_apply_relocations_add(pi->ehdr,
- sechdrs, i);
- else if (sechdrs[i].sh_type == SHT_REL)
- ret = arch_kexec_apply_relocations(pi->ehdr,
- sechdrs, i);
- if (ret)
- return ret;
- }
-
- return 0;
-}
-
-/* Load relocatable purgatory object and relocate it appropriately */
-int kexec_load_purgatory(struct kimage *image, unsigned long min,
- unsigned long max, int top_down,
- unsigned long *load_addr)
-{
- struct purgatory_info *pi = &image->purgatory_info;
- int ret;
-
- if (kexec_purgatory_size <= 0)
- return -EINVAL;
-
- if (kexec_purgatory_size < sizeof(Elf_Ehdr))
- return -ENOEXEC;
-
- pi->ehdr = (Elf_Ehdr *)kexec_purgatory;
-
- if (memcmp(pi->ehdr->e_ident, ELFMAG, SELFMAG) != 0
- || pi->ehdr->e_type != ET_REL
- || !elf_check_arch(pi->ehdr)
- || pi->ehdr->e_shentsize != sizeof(Elf_Shdr))
- return -ENOEXEC;
-
- if (pi->ehdr->e_shoff >= kexec_purgatory_size
- || (pi->ehdr->e_shnum * sizeof(Elf_Shdr) >
- kexec_purgatory_size - pi->ehdr->e_shoff))
- return -ENOEXEC;
-
- ret = __kexec_load_purgatory(image, min, max, top_down);
- if (ret)
- return ret;
-
- ret = kexec_apply_relocations(image);
- if (ret)
- goto out;
-
- *load_addr = pi->purgatory_load_addr;
- return 0;
-out:
- vfree(pi->sechdrs);
- vfree(pi->purgatory_buf);
- return ret;
-}
-
-static Elf_Sym *kexec_purgatory_find_symbol(struct purgatory_info *pi,
- const char *name)
-{
- Elf_Sym *syms;
- Elf_Shdr *sechdrs;
- Elf_Ehdr *ehdr;
- int i, k;
- const char *strtab;
-
- if (!pi->sechdrs || !pi->ehdr)
- return NULL;
-
- sechdrs = pi->sechdrs;
- ehdr = pi->ehdr;
-
- for (i = 0; i < ehdr->e_shnum; i++) {
- if (sechdrs[i].sh_type != SHT_SYMTAB)
- continue;
-
- if (sechdrs[i].sh_link >= ehdr->e_shnum)
- /* Invalid strtab section number */
- continue;
- strtab = (char *)sechdrs[sechdrs[i].sh_link].sh_offset;
- syms = (Elf_Sym *)sechdrs[i].sh_offset;
-
- /* Go through symbols for a match */
- for (k = 0; k < sechdrs[i].sh_size/sizeof(Elf_Sym); k++) {
- if (ELF_ST_BIND(syms[k].st_info) != STB_GLOBAL)
- continue;
-
- if (strcmp(strtab + syms[k].st_name, name) != 0)
- continue;
-
- if (syms[k].st_shndx == SHN_UNDEF ||
- syms[k].st_shndx >= ehdr->e_shnum) {
- pr_debug("Symbol: %s has bad section index %d.\n",
- name, syms[k].st_shndx);
- return NULL;
- }
-
- /* Found the symbol we are looking for */
- return &syms[k];
- }
- }
-
- return NULL;
-}
-
-void *kexec_purgatory_get_symbol_addr(struct kimage *image, const char *name)
-{
- struct purgatory_info *pi = &image->purgatory_info;
- Elf_Sym *sym;
- Elf_Shdr *sechdr;
-
- sym = kexec_purgatory_find_symbol(pi, name);
- if (!sym)
- return ERR_PTR(-EINVAL);
-
- sechdr = &pi->sechdrs[sym->st_shndx];
-
- /*
- * Returns the address where symbol will finally be loaded after
- * kexec_load_segment()
- */
- return (void *)(sechdr->sh_addr + sym->st_value);
-}
-
-/*
- * Get or set value of a symbol. If "get_value" is true, symbol value is
- * returned in buf otherwise symbol value is set based on value in buf.
- */
-int kexec_purgatory_get_set_symbol(struct kimage *image, const char *name,
- void *buf, unsigned int size, bool get_value)
-{
- Elf_Sym *sym;
- Elf_Shdr *sechdrs;
- struct purgatory_info *pi = &image->purgatory_info;
- char *sym_buf;
-
- sym = kexec_purgatory_find_symbol(pi, name);
- if (!sym)
- return -EINVAL;
-
- if (sym->st_size != size) {
- pr_err("symbol %s size mismatch: expected %lu actual %u\n",
- name, (unsigned long)sym->st_size, size);
- return -EINVAL;
- }
-
- sechdrs = pi->sechdrs;
-
- if (sechdrs[sym->st_shndx].sh_type == SHT_NOBITS) {
- pr_err("symbol %s is in a bss section. Cannot %s\n", name,
- get_value ? "get" : "set");
- return -EINVAL;
- }
-
- sym_buf = (unsigned char *)sechdrs[sym->st_shndx].sh_offset +
- sym->st_value;
-
- if (get_value)
- memcpy((void *)buf, sym_buf, size);
- else
- memcpy((void *)sym_buf, buf, size);
-
- return 0;
-}
-#endif /* CONFIG_KEXEC_FILE */
-
/*
* Move into place and start executing a preloaded standalone
* executable. If nothing was preloaded return an error.
diff -puN /dev/null kernel/kexec_file.c
--- /dev/null
+++ a/kernel/kexec_file.c
@@ -0,0 +1,1044 @@
+/*
+ * kexec: kexec_file_load system call
+ *
+ * Copyright (C) 2014 Red Hat Inc.
+ * Authors:
+ * Vivek Goyal <vgoyal@xxxxxxxxxx>
+ *
+ * This source code is licensed under the GNU General Public License,
+ * Version 2. See the file COPYING for more details.
+ */
+
+#include <linux/capability.h>
+#include <linux/mm.h>
+#include <linux/file.h>
+#include <linux/slab.h>
+#include <linux/kexec.h>
+#include <linux/mutex.h>
+#include <linux/list.h>
+#include <crypto/hash.h>
+#include <crypto/sha.h>
+#include <linux/syscalls.h>
+#include <linux/vmalloc.h>
+#include "kexec_internal.h"
+
+/*
+ * Declare these symbols weak so that if architecture provides a purgatory,
+ * these will be overridden.
+ */
+char __weak kexec_purgatory[0];
+size_t __weak kexec_purgatory_size = 0;
+
+static int kexec_calculate_store_digests(struct kimage *image);
+
+static int copy_file_from_fd(int fd, void **buf, unsigned long *buf_len)
+{
+ struct fd f = fdget(fd);
+ int ret;
+ struct kstat stat;
+ loff_t pos;
+ ssize_t bytes = 0;
+
+ if (!f.file)
+ return -EBADF;
+
+ ret = vfs_getattr(&f.file->f_path, &stat);
+ if (ret)
+ goto out;
+
+ if (stat.size > INT_MAX) {
+ ret = -EFBIG;
+ goto out;
+ }
+
+ /* Don't hand 0 to vmalloc, it whines. */
+ if (stat.size == 0) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ *buf = vmalloc(stat.size);
+ if (!*buf) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ pos = 0;
+ while (pos < stat.size) {
+ bytes = kernel_read(f.file, pos, (char *)(*buf) + pos,
+ stat.size - pos);
+ if (bytes < 0) {
+ vfree(*buf);
+ ret = bytes;
+ goto out;
+ }
+
+ if (bytes == 0)
+ break;
+ pos += bytes;
+ }
+
+ if (pos != stat.size) {
+ ret = -EBADF;
+ vfree(*buf);
+ goto out;
+ }
+
+ *buf_len = pos;
+out:
+ fdput(f);
+ return ret;
+}
+
+/* Architectures can provide this probe function */
+int __weak arch_kexec_kernel_image_probe(struct kimage *image, void *buf,
+ unsigned long buf_len)
+{
+ return -ENOEXEC;
+}
+
+void * __weak arch_kexec_kernel_image_load(struct kimage *image)
+{
+ return ERR_PTR(-ENOEXEC);
+}
+
+void __weak arch_kimage_file_post_load_cleanup(struct kimage *image)
+{
+}
+
+int __weak arch_kexec_kernel_verify_sig(struct kimage *image, void *buf,
+ unsigned long buf_len)
+{
+ return -EKEYREJECTED;
+}
+
+/* Apply relocations of type RELA */
+int __weak
+arch_kexec_apply_relocations_add(const Elf_Ehdr *ehdr, Elf_Shdr *sechdrs,
+ unsigned int relsec)
+{
+ pr_err("RELA relocation unsupported.\n");
+ return -ENOEXEC;
+}
+
+/* Apply relocations of type REL */
+int __weak
+arch_kexec_apply_relocations(const Elf_Ehdr *ehdr, Elf_Shdr *sechdrs,
+ unsigned int relsec)
+{
+ pr_err("REL relocation unsupported.\n");
+ return -ENOEXEC;
+}
+
+/*
+ * Free up memory used by kernel, initrd, and command line. This is temporary
+ * memory allocation which is not needed any more after these buffers have
+ * been loaded into separate segments and have been copied elsewhere.
+ */
+void kimage_file_post_load_cleanup(struct kimage *image)
+{
+ struct purgatory_info *pi = &image->purgatory_info;
+
+ vfree(image->kernel_buf);
+ image->kernel_buf = NULL;
+
+ vfree(image->initrd_buf);
+ image->initrd_buf = NULL;
+
+ kfree(image->cmdline_buf);
+ image->cmdline_buf = NULL;
+
+ vfree(pi->purgatory_buf);
+ pi->purgatory_buf = NULL;
+
+ vfree(pi->sechdrs);
+ pi->sechdrs = NULL;
+
+ /* See if architecture has anything to cleanup post load */
+ arch_kimage_file_post_load_cleanup(image);
+
+ /*
+ * Above call should have called into bootloader to free up
+ * any data stored in kimage->image_loader_data. It should
+ * be ok now to free it up.
+ */
+ kfree(image->image_loader_data);
+ image->image_loader_data = NULL;
+}
+
+/*
+ * In file mode list of segments is prepared by kernel. Copy relevant
+ * data from user space, do error checking, prepare segment list
+ */
+static int
+kimage_file_prepare_segments(struct kimage *image, int kernel_fd, int initrd_fd,
+ const char __user *cmdline_ptr,
+ unsigned long cmdline_len, unsigned flags)
+{
+ int ret = 0;
+ void *ldata;
+
+ ret = copy_file_from_fd(kernel_fd, &image->kernel_buf,
+ &image->kernel_buf_len);
+ if (ret)
+ return ret;
+
+ /* Call arch image probe handlers */
+ ret = arch_kexec_kernel_image_probe(image, image->kernel_buf,
+ image->kernel_buf_len);
+
+ if (ret)
+ goto out;
+
+#ifdef CONFIG_KEXEC_VERIFY_SIG
+ ret = arch_kexec_kernel_verify_sig(image, image->kernel_buf,
+ image->kernel_buf_len);
+ if (ret) {
+ pr_debug("kernel signature verification failed.\n");
+ goto out;
+ }
+ pr_debug("kernel signature verification successful.\n");
+#endif
+ /* It is possible that there no initramfs is being loaded */
+ if (!(flags & KEXEC_FILE_NO_INITRAMFS)) {
+ ret = copy_file_from_fd(initrd_fd, &image->initrd_buf,
+ &image->initrd_buf_len);
+ if (ret)
+ goto out;
+ }
+
+ if (cmdline_len) {
+ image->cmdline_buf = kzalloc(cmdline_len, GFP_KERNEL);
+ if (!image->cmdline_buf) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ ret = copy_from_user(image->cmdline_buf, cmdline_ptr,
+ cmdline_len);
+ if (ret) {
+ ret = -EFAULT;
+ goto out;
+ }
+
+ image->cmdline_buf_len = cmdline_len;
+
+ /* command line should be a string with last byte null */
+ if (image->cmdline_buf[cmdline_len - 1] != '\0') {
+ ret = -EINVAL;
+ goto out;
+ }
+ }
+
+ /* Call arch image load handlers */
+ ldata = arch_kexec_kernel_image_load(image);
+
+ if (IS_ERR(ldata)) {
+ ret = PTR_ERR(ldata);
+ goto out;
+ }
+
+ image->image_loader_data = ldata;
+out:
+ /* In case of error, free up all allocated memory in this function */
+ if (ret)
+ kimage_file_post_load_cleanup(image);
+ return ret;
+}
+
+static int
+kimage_file_alloc_init(struct kimage **rimage, int kernel_fd,
+ int initrd_fd, const char __user *cmdline_ptr,
+ unsigned long cmdline_len, unsigned long flags)
+{
+ int ret;
+ struct kimage *image;
+ bool kexec_on_panic = flags & KEXEC_FILE_ON_CRASH;
+
+ image = do_kimage_alloc_init();
+ if (!image)
+ return -ENOMEM;
+
+ image->file_mode = 1;
+
+ if (kexec_on_panic) {
+ /* Enable special crash kernel control page alloc policy. */
+ image->control_page = crashk_res.start;
+ image->type = KEXEC_TYPE_CRASH;
+ }
+
+ ret = kimage_file_prepare_segments(image, kernel_fd, initrd_fd,
+ cmdline_ptr, cmdline_len, flags);
+ if (ret)
+ goto out_free_image;
+
+ ret = sanity_check_segment_list(image);
+ if (ret)
+ goto out_free_post_load_bufs;
+
+ ret = -ENOMEM;
+ image->control_code_page = kimage_alloc_control_pages(image,
+ get_order(KEXEC_CONTROL_PAGE_SIZE));
+ if (!image->control_code_page) {
+ pr_err("Could not allocate control_code_buffer\n");
+ goto out_free_post_load_bufs;
+ }
+
+ if (!kexec_on_panic) {
+ image->swap_page = kimage_alloc_control_pages(image, 0);
+ if (!image->swap_page) {
+ pr_err("Could not allocate swap buffer\n");
+ goto out_free_control_pages;
+ }
+ }
+
+ *rimage = image;
+ return 0;
+out_free_control_pages:
+ kimage_free_page_list(&image->control_pages);
+out_free_post_load_bufs:
+ kimage_file_post_load_cleanup(image);
+out_free_image:
+ kfree(image);
+ return ret;
+}
+
+SYSCALL_DEFINE5(kexec_file_load, int, kernel_fd, int, initrd_fd,
+ unsigned long, cmdline_len, const char __user *, cmdline_ptr,
+ unsigned long, flags)
+{
+ int ret = 0, i;
+ struct kimage **dest_image, *image;
+
+ /* We only trust the superuser with rebooting the system. */
+ if (!capable(CAP_SYS_BOOT) || kexec_load_disabled)
+ return -EPERM;
+
+ /* Make sure we have a legal set of flags */
+ if (flags != (flags & KEXEC_FILE_FLAGS))
+ return -EINVAL;
+
+ image = NULL;
+
+ if (!mutex_trylock(&kexec_mutex))
+ return -EBUSY;
+
+ dest_image = &kexec_image;
+ if (flags & KEXEC_FILE_ON_CRASH)
+ dest_image = &kexec_crash_image;
+
+ if (flags & KEXEC_FILE_UNLOAD)
+ goto exchange;
+
+ /*
+ * In case of crash, new kernel gets loaded in reserved region. It is
+ * same memory where old crash kernel might be loaded. Free any
+ * current crash dump kernel before we corrupt it.
+ */
+ if (flags & KEXEC_FILE_ON_CRASH)
+ kimage_free(xchg(&kexec_crash_image, NULL));
+
+ ret = kimage_file_alloc_init(&image, kernel_fd, initrd_fd, cmdline_ptr,
+ cmdline_len, flags);
+ if (ret)
+ goto out;
+
+ ret = machine_kexec_prepare(image);
+ if (ret)
+ goto out;
+
+ ret = kexec_calculate_store_digests(image);
+ if (ret)
+ goto out;
+
+ for (i = 0; i < image->nr_segments; i++) {
+ struct kexec_segment *ksegment;
+
+ ksegment = &image->segment[i];
+ pr_debug("Loading segment %d: buf=0x%p bufsz=0x%zx mem=0x%lx memsz=0x%zx\n",
+ i, ksegment->buf, ksegment->bufsz, ksegment->mem,
+ ksegment->memsz);
+
+ ret = kimage_load_segment(image, &image->segment[i]);
+ if (ret)
+ goto out;
+ }
+
+ kimage_terminate(image);
+
+ /*
+ * Free up any temporary buffers allocated which are not needed
+ * after image has been loaded
+ */
+ kimage_file_post_load_cleanup(image);
+exchange:
+ image = xchg(dest_image, image);
+out:
+ mutex_unlock(&kexec_mutex);
+ kimage_free(image);
+ return ret;
+}
+
+static int locate_mem_hole_top_down(unsigned long start, unsigned long end,
+ struct kexec_buf *kbuf)
+{
+ struct kimage *image = kbuf->image;
+ unsigned long temp_start, temp_end;
+
+ temp_end = min(end, kbuf->buf_max);
+ temp_start = temp_end - kbuf->memsz;
+
+ do {
+ /* align down start */
+ temp_start = temp_start & (~(kbuf->buf_align - 1));
+
+ if (temp_start < start || temp_start < kbuf->buf_min)
+ return 0;
+
+ temp_end = temp_start + kbuf->memsz - 1;
+
+ /*
+ * Make sure this does not conflict with any of existing
+ * segments
+ */
+ if (kimage_is_destination_range(image, temp_start, temp_end)) {
+ temp_start = temp_start - PAGE_SIZE;
+ continue;
+ }
+
+ /* We found a suitable memory range */
+ break;
+ } while (1);
+
+ /* If we are here, we found a suitable memory range */
+ kbuf->mem = temp_start;
+
+ /* Success, stop navigating through remaining System RAM ranges */
+ return 1;
+}
+
+static int locate_mem_hole_bottom_up(unsigned long start, unsigned long end,
+ struct kexec_buf *kbuf)
+{
+ struct kimage *image = kbuf->image;
+ unsigned long temp_start, temp_end;
+
+ temp_start = max(start, kbuf->buf_min);
+
+ do {
+ temp_start = ALIGN(temp_start, kbuf->buf_align);
+ temp_end = temp_start + kbuf->memsz - 1;
+
+ if (temp_end > end || temp_end > kbuf->buf_max)
+ return 0;
+ /*
+ * Make sure this does not conflict with any of existing
+ * segments
+ */
+ if (kimage_is_destination_range(image, temp_start, temp_end)) {
+ temp_start = temp_start + PAGE_SIZE;
+ continue;
+ }
+
+ /* We found a suitable memory range */
+ break;
+ } while (1);
+
+ /* If we are here, we found a suitable memory range */
+ kbuf->mem = temp_start;
+
+ /* Success, stop navigating through remaining System RAM ranges */
+ return 1;
+}
+
+static int locate_mem_hole_callback(u64 start, u64 end, void *arg)
+{
+ struct kexec_buf *kbuf = (struct kexec_buf *)arg;
+ unsigned long sz = end - start + 1;
+
+ /* Returning 0 will take to next memory range */
+ if (sz < kbuf->memsz)
+ return 0;
+
+ if (end < kbuf->buf_min || start > kbuf->buf_max)
+ return 0;
+
+ /*
+ * Allocate memory top down with-in ram range. Otherwise bottom up
+ * allocation.
+ */
+ if (kbuf->top_down)
+ return locate_mem_hole_top_down(start, end, kbuf);
+ return locate_mem_hole_bottom_up(start, end, kbuf);
+}
+
+/*
+ * Helper function for placing a buffer in a kexec segment. This assumes
+ * that kexec_mutex is held.
+ */
+int kexec_add_buffer(struct kimage *image, char *buffer, unsigned long bufsz,
+ unsigned long memsz, unsigned long buf_align,
+ unsigned long buf_min, unsigned long buf_max,
+ bool top_down, unsigned long *load_addr)
+{
+
+ struct kexec_segment *ksegment;
+ struct kexec_buf buf, *kbuf;
+ int ret;
+
+ /* Currently adding segment this way is allowed only in file mode */
+ if (!image->file_mode)
+ return -EINVAL;
+
+ if (image->nr_segments >= KEXEC_SEGMENT_MAX)
+ return -EINVAL;
+
+ /*
+ * Make sure we are not trying to add buffer after allocating
+ * control pages. All segments need to be placed first before
+ * any control pages are allocated. As control page allocation
+ * logic goes through list of segments to make sure there are
+ * no destination overlaps.
+ */
+ if (!list_empty(&image->control_pages)) {
+ WARN_ON(1);
+ return -EINVAL;
+ }
+
+ memset(&buf, 0, sizeof(struct kexec_buf));
+ kbuf = &buf;
+ kbuf->image = image;
+ kbuf->buffer = buffer;
+ kbuf->bufsz = bufsz;
+
+ kbuf->memsz = ALIGN(memsz, PAGE_SIZE);
+ kbuf->buf_align = max(buf_align, PAGE_SIZE);
+ kbuf->buf_min = buf_min;
+ kbuf->buf_max = buf_max;
+ kbuf->top_down = top_down;
+
+ /* Walk the RAM ranges and allocate a suitable range for the buffer */
+ if (image->type == KEXEC_TYPE_CRASH)
+ ret = walk_iomem_res("Crash kernel",
+ IORESOURCE_MEM | IORESOURCE_BUSY,
+ crashk_res.start, crashk_res.end, kbuf,
+ locate_mem_hole_callback);
+ else
+ ret = walk_system_ram_res(0, -1, kbuf,
+ locate_mem_hole_callback);
+ if (ret != 1) {
+ /* A suitable memory range could not be found for buffer */
+ return -EADDRNOTAVAIL;
+ }
+
+ /* Found a suitable memory range */
+ ksegment = &image->segment[image->nr_segments];
+ ksegment->kbuf = kbuf->buffer;
+ ksegment->bufsz = kbuf->bufsz;
+ ksegment->mem = kbuf->mem;
+ ksegment->memsz = kbuf->memsz;
+ image->nr_segments++;
+ *load_addr = ksegment->mem;
+ return 0;
+}
+
+/* Calculate and store the digest of segments */
+static int kexec_calculate_store_digests(struct kimage *image)
+{
+ struct crypto_shash *tfm;
+ struct shash_desc *desc;
+ int ret = 0, i, j, zero_buf_sz, sha_region_sz;
+ size_t desc_size, nullsz;
+ char *digest;
+ void *zero_buf;
+ struct kexec_sha_region *sha_regions;
+ struct purgatory_info *pi = &image->purgatory_info;
+
+ zero_buf = __va(page_to_pfn(ZERO_PAGE(0)) << PAGE_SHIFT);
+ zero_buf_sz = PAGE_SIZE;
+
+ tfm = crypto_alloc_shash("sha256", 0, 0);
+ if (IS_ERR(tfm)) {
+ ret = PTR_ERR(tfm);
+ goto out;
+ }
+
+ desc_size = crypto_shash_descsize(tfm) + sizeof(*desc);
+ desc = kzalloc(desc_size, GFP_KERNEL);
+ if (!desc) {
+ ret = -ENOMEM;
+ goto out_free_tfm;
+ }
+
+ sha_region_sz = KEXEC_SEGMENT_MAX * sizeof(struct kexec_sha_region);
+ sha_regions = vzalloc(sha_region_sz);
+ if (!sha_regions)
+ goto out_free_desc;
+
+ desc->tfm = tfm;
+ desc->flags = 0;
+
+ ret = crypto_shash_init(desc);
+ if (ret < 0)
+ goto out_free_sha_regions;
+
+ digest = kzalloc(SHA256_DIGEST_SIZE, GFP_KERNEL);
+ if (!digest) {
+ ret = -ENOMEM;
+ goto out_free_sha_regions;
+ }
+
+ for (j = i = 0; i < image->nr_segments; i++) {
+ struct kexec_segment *ksegment;
+
+ ksegment = &image->segment[i];
+ /*
+ * Skip purgatory as it will be modified once we put digest
+ * info in purgatory.
+ */
+ if (ksegment->kbuf == pi->purgatory_buf)
+ continue;
+
+ ret = crypto_shash_update(desc, ksegment->kbuf,
+ ksegment->bufsz);
+ if (ret)
+ break;
+
+ /*
+ * Assume rest of the buffer is filled with zero and
+ * update digest accordingly.
+ */
+ nullsz = ksegment->memsz - ksegment->bufsz;
+ while (nullsz) {
+ unsigned long bytes = nullsz;
+
+ if (bytes > zero_buf_sz)
+ bytes = zero_buf_sz;
+ ret = crypto_shash_update(desc, zero_buf, bytes);
+ if (ret)
+ break;
+ nullsz -= bytes;
+ }
+
+ if (ret)
+ break;
+
+ sha_regions[j].start = ksegment->mem;
+ sha_regions[j].len = ksegment->memsz;
+ j++;
+ }
+
+ if (!ret) {
+ ret = crypto_shash_final(desc, digest);
+ if (ret)
+ goto out_free_digest;
+ ret = kexec_purgatory_get_set_symbol(image, "sha_regions",
+ sha_regions, sha_region_sz, 0);
+ if (ret)
+ goto out_free_digest;
+
+ ret = kexec_purgatory_get_set_symbol(image, "sha256_digest",
+ digest, SHA256_DIGEST_SIZE, 0);
+ if (ret)
+ goto out_free_digest;
+ }
+
+out_free_digest:
+ kfree(digest);
+out_free_sha_regions:
+ vfree(sha_regions);
+out_free_desc:
+ kfree(desc);
+out_free_tfm:
+ kfree(tfm);
+out:
+ return ret;
+}
+
+/* Actually load purgatory. Lot of code taken from kexec-tools */
+static int __kexec_load_purgatory(struct kimage *image, unsigned long min,
+ unsigned long max, int top_down)
+{
+ struct purgatory_info *pi = &image->purgatory_info;
+ unsigned long align, buf_align, bss_align, buf_sz, bss_sz, bss_pad;
+ unsigned long memsz, entry, load_addr, curr_load_addr, bss_addr, offset;
+ unsigned char *buf_addr, *src;
+ int i, ret = 0, entry_sidx = -1;
+ const Elf_Shdr *sechdrs_c;
+ Elf_Shdr *sechdrs = NULL;
+ void *purgatory_buf = NULL;
+
+ /*
+ * sechdrs_c points to section headers in purgatory and are read
+ * only. No modifications allowed.
+ */
+ sechdrs_c = (void *)pi->ehdr + pi->ehdr->e_shoff;
+
+ /*
+ * We can not modify sechdrs_c[] and its fields. It is read only.
+ * Copy it over to a local copy where one can store some temporary
+ * data and free it at the end. We need to modify ->sh_addr and
+ * ->sh_offset fields to keep track of permanent and temporary
+ * locations of sections.
+ */
+ sechdrs = vzalloc(pi->ehdr->e_shnum * sizeof(Elf_Shdr));
+ if (!sechdrs)
+ return -ENOMEM;
+
+ memcpy(sechdrs, sechdrs_c, pi->ehdr->e_shnum * sizeof(Elf_Shdr));
+
+ /*
+ * We seem to have multiple copies of sections. First copy is which
+ * is embedded in kernel in read only section. Some of these sections
+ * will be copied to a temporary buffer and relocated. And these
+ * sections will finally be copied to their final destination at
+ * segment load time.
+ *
+ * Use ->sh_offset to reflect section address in memory. It will
+ * point to original read only copy if section is not allocatable.
+ * Otherwise it will point to temporary copy which will be relocated.
+ *
+ * Use ->sh_addr to contain final address of the section where it
+ * will go during execution time.
+ */
+ for (i = 0; i < pi->ehdr->e_shnum; i++) {
+ if (sechdrs[i].sh_type == SHT_NOBITS)
+ continue;
+
+ sechdrs[i].sh_offset = (unsigned long)pi->ehdr +
+ sechdrs[i].sh_offset;
+ }
+
+ /*
+ * Identify entry point section and make entry relative to section
+ * start.
+ */
+ entry = pi->ehdr->e_entry;
+ for (i = 0; i < pi->ehdr->e_shnum; i++) {
+ if (!(sechdrs[i].sh_flags & SHF_ALLOC))
+ continue;
+
+ if (!(sechdrs[i].sh_flags & SHF_EXECINSTR))
+ continue;
+
+ /* Make entry section relative */
+ if (sechdrs[i].sh_addr <= pi->ehdr->e_entry &&
+ ((sechdrs[i].sh_addr + sechdrs[i].sh_size) >
+ pi->ehdr->e_entry)) {
+ entry_sidx = i;
+ entry -= sechdrs[i].sh_addr;
+ break;
+ }
+ }
+
+ /* Determine how much memory is needed to load relocatable object. */
+ buf_align = 1;
+ bss_align = 1;
+ buf_sz = 0;
+ bss_sz = 0;
+
+ for (i = 0; i < pi->ehdr->e_shnum; i++) {
+ if (!(sechdrs[i].sh_flags & SHF_ALLOC))
+ continue;
+
+ align = sechdrs[i].sh_addralign;
+ if (sechdrs[i].sh_type != SHT_NOBITS) {
+ if (buf_align < align)
+ buf_align = align;
+ buf_sz = ALIGN(buf_sz, align);
+ buf_sz += sechdrs[i].sh_size;
+ } else {
+ /* bss section */
+ if (bss_align < align)
+ bss_align = align;
+ bss_sz = ALIGN(bss_sz, align);
+ bss_sz += sechdrs[i].sh_size;
+ }
+ }
+
+ /* Determine the bss padding required to align bss properly */
+ bss_pad = 0;
+ if (buf_sz & (bss_align - 1))
+ bss_pad = bss_align - (buf_sz & (bss_align - 1));
+
+ memsz = buf_sz + bss_pad + bss_sz;
+
+ /* Allocate buffer for purgatory */
+ purgatory_buf = vzalloc(buf_sz);
+ if (!purgatory_buf) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ if (buf_align < bss_align)
+ buf_align = bss_align;
+
+ /* Add buffer to segment list */
+ ret = kexec_add_buffer(image, purgatory_buf, buf_sz, memsz,
+ buf_align, min, max, top_down,
+ &pi->purgatory_load_addr);
+ if (ret)
+ goto out;
+
+ /* Load SHF_ALLOC sections */
+ buf_addr = purgatory_buf;
+ load_addr = curr_load_addr = pi->purgatory_load_addr;
+ bss_addr = load_addr + buf_sz + bss_pad;
+
+ for (i = 0; i < pi->ehdr->e_shnum; i++) {
+ if (!(sechdrs[i].sh_flags & SHF_ALLOC))
+ continue;
+
+ align = sechdrs[i].sh_addralign;
+ if (sechdrs[i].sh_type != SHT_NOBITS) {
+ curr_load_addr = ALIGN(curr_load_addr, align);
+ offset = curr_load_addr - load_addr;
+ /* We already modifed ->sh_offset to keep src addr */
+ src = (char *) sechdrs[i].sh_offset;
+ memcpy(buf_addr + offset, src, sechdrs[i].sh_size);
+
+ /* Store load address and source address of section */
+ sechdrs[i].sh_addr = curr_load_addr;
+
+ /*
+ * This section got copied to temporary buffer. Update
+ * ->sh_offset accordingly.
+ */
+ sechdrs[i].sh_offset = (unsigned long)(buf_addr + offset);
+
+ /* Advance to the next address */
+ curr_load_addr += sechdrs[i].sh_size;
+ } else {
+ bss_addr = ALIGN(bss_addr, align);
+ sechdrs[i].sh_addr = bss_addr;
+ bss_addr += sechdrs[i].sh_size;
+ }
+ }
+
+ /* Update entry point based on load address of text section */
+ if (entry_sidx >= 0)
+ entry += sechdrs[entry_sidx].sh_addr;
+
+ /* Make kernel jump to purgatory after shutdown */
+ image->start = entry;
+
+ /* Used later to get/set symbol values */
+ pi->sechdrs = sechdrs;
+
+ /*
+ * Used later to identify which section is purgatory and skip it
+ * from checksumming.
+ */
+ pi->purgatory_buf = purgatory_buf;
+ return ret;
+out:
+ vfree(sechdrs);
+ vfree(purgatory_buf);
+ return ret;
+}
+
+static int kexec_apply_relocations(struct kimage *image)
+{
+ int i, ret;
+ struct purgatory_info *pi = &image->purgatory_info;
+ Elf_Shdr *sechdrs = pi->sechdrs;
+
+ /* Apply relocations */
+ for (i = 0; i < pi->ehdr->e_shnum; i++) {
+ Elf_Shdr *section, *symtab;
+
+ if (sechdrs[i].sh_type != SHT_RELA &&
+ sechdrs[i].sh_type != SHT_REL)
+ continue;
+
+ /*
+ * For section of type SHT_RELA/SHT_REL,
+ * ->sh_link contains section header index of associated
+ * symbol table. And ->sh_info contains section header
+ * index of section to which relocations apply.
+ */
+ if (sechdrs[i].sh_info >= pi->ehdr->e_shnum ||
+ sechdrs[i].sh_link >= pi->ehdr->e_shnum)
+ return -ENOEXEC;
+
+ section = &sechdrs[sechdrs[i].sh_info];
+ symtab = &sechdrs[sechdrs[i].sh_link];
+
+ if (!(section->sh_flags & SHF_ALLOC))
+ continue;
+
+ /*
+ * symtab->sh_link contain section header index of associated
+ * string table.
+ */
+ if (symtab->sh_link >= pi->ehdr->e_shnum)
+ /* Invalid section number? */
+ continue;
+
+ /*
+ * Respective architecture needs to provide support for applying
+ * relocations of type SHT_RELA/SHT_REL.
+ */
+ if (sechdrs[i].sh_type == SHT_RELA)
+ ret = arch_kexec_apply_relocations_add(pi->ehdr,
+ sechdrs, i);
+ else if (sechdrs[i].sh_type == SHT_REL)
+ ret = arch_kexec_apply_relocations(pi->ehdr,
+ sechdrs, i);
+ if (ret)
+ return ret;
+ }
+
+ return 0;
+}
+
+/* Load relocatable purgatory object and relocate it appropriately */
+int kexec_load_purgatory(struct kimage *image, unsigned long min,
+ unsigned long max, int top_down,
+ unsigned long *load_addr)
+{
+ struct purgatory_info *pi = &image->purgatory_info;
+ int ret;
+
+ if (kexec_purgatory_size <= 0)
+ return -EINVAL;
+
+ if (kexec_purgatory_size < sizeof(Elf_Ehdr))
+ return -ENOEXEC;
+
+ pi->ehdr = (Elf_Ehdr *)kexec_purgatory;
+
+ if (memcmp(pi->ehdr->e_ident, ELFMAG, SELFMAG) != 0
+ || pi->ehdr->e_type != ET_REL
+ || !elf_check_arch(pi->ehdr)
+ || pi->ehdr->e_shentsize != sizeof(Elf_Shdr))
+ return -ENOEXEC;
+
+ if (pi->ehdr->e_shoff >= kexec_purgatory_size
+ || (pi->ehdr->e_shnum * sizeof(Elf_Shdr) >
+ kexec_purgatory_size - pi->ehdr->e_shoff))
+ return -ENOEXEC;
+
+ ret = __kexec_load_purgatory(image, min, max, top_down);
+ if (ret)
+ return ret;
+
+ ret = kexec_apply_relocations(image);
+ if (ret)
+ goto out;
+
+ *load_addr = pi->purgatory_load_addr;
+ return 0;
+out:
+ vfree(pi->sechdrs);
+ vfree(pi->purgatory_buf);
+ return ret;
+}
+
+static Elf_Sym *kexec_purgatory_find_symbol(struct purgatory_info *pi,
+ const char *name)
+{
+ Elf_Sym *syms;
+ Elf_Shdr *sechdrs;
+ Elf_Ehdr *ehdr;
+ int i, k;
+ const char *strtab;
+
+ if (!pi->sechdrs || !pi->ehdr)
+ return NULL;
+
+ sechdrs = pi->sechdrs;
+ ehdr = pi->ehdr;
+
+ for (i = 0; i < ehdr->e_shnum; i++) {
+ if (sechdrs[i].sh_type != SHT_SYMTAB)
+ continue;
+
+ if (sechdrs[i].sh_link >= ehdr->e_shnum)
+ /* Invalid strtab section number */
+ continue;
+ strtab = (char *)sechdrs[sechdrs[i].sh_link].sh_offset;
+ syms = (Elf_Sym *)sechdrs[i].sh_offset;
+
+ /* Go through symbols for a match */
+ for (k = 0; k < sechdrs[i].sh_size/sizeof(Elf_Sym); k++) {
+ if (ELF_ST_BIND(syms[k].st_info) != STB_GLOBAL)
+ continue;
+
+ if (strcmp(strtab + syms[k].st_name, name) != 0)
+ continue;
+
+ if (syms[k].st_shndx == SHN_UNDEF ||
+ syms[k].st_shndx >= ehdr->e_shnum) {
+ pr_debug("Symbol: %s has bad section index %d.\n",
+ name, syms[k].st_shndx);
+ return NULL;
+ }
+
+ /* Found the symbol we are looking for */
+ return &syms[k];
+ }
+ }
+
+ return NULL;
+}
+
+void *kexec_purgatory_get_symbol_addr(struct kimage *image, const char *name)
+{
+ struct purgatory_info *pi = &image->purgatory_info;
+ Elf_Sym *sym;
+ Elf_Shdr *sechdr;
+
+ sym = kexec_purgatory_find_symbol(pi, name);
+ if (!sym)
+ return ERR_PTR(-EINVAL);
+
+ sechdr = &pi->sechdrs[sym->st_shndx];
+
+ /*
+ * Returns the address where symbol will finally be loaded after
+ * kexec_load_segment()
+ */
+ return (void *)(sechdr->sh_addr + sym->st_value);
+}
+
+/*
+ * Get or set value of a symbol. If "get_value" is true, symbol value is
+ * returned in buf otherwise symbol value is set based on value in buf.
+ */
+int kexec_purgatory_get_set_symbol(struct kimage *image, const char *name,
+ void *buf, unsigned int size, bool get_value)
+{
+ Elf_Sym *sym;
+ Elf_Shdr *sechdrs;
+ struct purgatory_info *pi = &image->purgatory_info;
+ char *sym_buf;
+
+ sym = kexec_purgatory_find_symbol(pi, name);
+ if (!sym)
+ return -EINVAL;
+
+ if (sym->st_size != size) {
+ pr_err("symbol %s size mismatch: expected %lu actual %u\n",
+ name, (unsigned long)sym->st_size, size);
+ return -EINVAL;
+ }
+
+ sechdrs = pi->sechdrs;
+
+ if (sechdrs[sym->st_shndx].sh_type == SHT_NOBITS) {
+ pr_err("symbol %s is in a bss section. Cannot %s\n", name,
+ get_value ? "get" : "set");
+ return -EINVAL;
+ }
+
+ sym_buf = (unsigned char *)sechdrs[sym->st_shndx].sh_offset +
+ sym->st_value;
+
+ if (get_value)
+ memcpy((void *)buf, sym_buf, size);
+ else
+ memcpy((void *)sym_buf, buf, size);
+
+ return 0;
+}
diff -puN /dev/null kernel/kexec_internal.h
--- /dev/null
+++ a/kernel/kexec_internal.h
@@ -0,0 +1,22 @@
+#ifndef LINUX_KEXEC_INTERNAL_H
+#define LINUX_KEXEC_INTERNAL_H
+
+#include <linux/kexec.h>
+
+struct kimage *do_kimage_alloc_init(void);
+int sanity_check_segment_list(struct kimage *image);
+void kimage_free_page_list(struct list_head *list);
+void kimage_free(struct kimage *image);
+int kimage_load_segment(struct kimage *image, struct kexec_segment *segment);
+void kimage_terminate(struct kimage *image);
+int kimage_is_destination_range(struct kimage *image,
+ unsigned long start, unsigned long end);
+
+extern struct mutex kexec_mutex;
+
+#ifdef CONFIG_KEXEC_FILE
+void kimage_file_post_load_cleanup(struct kimage *image);
+#else /* CONFIG_KEXEC_FILE */
+static inline void kimage_file_post_load_cleanup(struct kimage *image) { }
+#endif /* CONFIG_KEXEC_FILE */
+#endif /* LINUX_KEXEC_INTERNAL_H */
_
Patches currently in -mm which might be from dyoung@xxxxxxxxxx are
kexec-split-kexec_file-syscall-code-to-kexec_filec.patch
kexec-split-kexec_load-syscall-from-kexec-core-code.patch
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